JP2022113518A - Information acquisition device - Google Patents

Abstract

To provide an information acquisition device which makes it easier to acquire accurate information inside a living body compared with devices of transmissive and reflective types.SOLUTION: An information acquisition device provided herein comprises an output source for irradiating a target body with a detection wave, and a receiver unit capable of receiving the detection wave irradiated onto the target body. The output source and the receiver unit are arranged such that a direction of the detection wave irradiating the target body from the output source is at an obtuse angle with a direction from an irradiated point, irradiated with the detection wave, on the target body to the receiver unit.SELECTED DRAWING: Figure 1

Description

The present invention relates to an information acquisition device capable of noninvasively acquiring biological information by irradiating a living body with detection waves such as light.

In recent years, against the backdrop of growing health consciousness, information acquisition devices have been developed that can be used as indicators of health conditions and advice on lifestyle-related diseases by non-invasively analyzing the shape of blood vessels and blood components inside the body. there is
As such an information acquisition device, a detection wave such as light is applied to a living body and the detection wave reflected from the living body is used as a noninvasive method of measuring biological information (see FIG. 9). A transmissive type (see FIG. 10) that utilizes a detection wave that passes through the rear surface of the transmissive type is used (see, for example, Patent Document 1).

It should be noted that not only visible light wavelengths but also near-infrared wavelengths (>700 nm) are used in detection waves of information acquisition devices for observing the inside of a living body so that information deeper into the living body can be obtained.
The information acquisition device 211 shown in FIG. 9 and the information acquisition device 312 shown in FIG. The wavelength band to be used as the detection wave can be determined from the balance of the absorbance of hemoglobin in .

For the near-infrared wavelengths, when silicon semiconductors are used, for example, due to the physical properties of the material, it is not possible to obtain information on the inside of the body, such as blood vessels, unless strong light corresponding to several watts or more is input as the output sources 220 and 320. . Therefore, it is difficult to apply it to a portable device because of its high power consumption, and so far, it has been limited to applications such as palm vein authentication, which is relatively on the surface.

On the other hand, the recent development of sensor devices by various companies has improved their sensitivity and performance, and even silicon semiconductors, which are advantageous for functional integration, have high sensitivity performance in the band exceeding 850 nm, which is a longer wavelength. are beginning to be obtained.

JP-A-2003-331272

As shown in FIG. 9, in a conventional reflective information acquisition device 211, a target living body (for example, a finger) is irradiated with light from an LED as an output source 220, and the transmitted wave is detected by a receiving section 240. , and the angle B shown in FIG. 9 approximates 0 degree. In this conventional reflective information acquisition device 211, the detection wave reflected from the surface of the living body is strongly reflected, and the information on the surface of the living body (for example, fingerprints on the surface) is exaggerated and becomes noise, so that the information inside the living body cannot be obtained accurately. Hard to get.

Further, as shown in FIG. 10, in the conventional transmissive information acquisition device 312, a target living body (for example, a finger) is irradiated with light from an LED as an output source 320, and the transmitted wave is detected by a receiving unit 350. The angle C shown in FIG. 10 is 180 degrees.
In this conventional transmissive information acquisition device 312, the distance that the detection wave travels inside the living body is long, and the detection wave is greatly attenuated, making it difficult to accurately obtain information on the inside of the living body.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an information acquisition apparatus that can more accurately and easily obtain information on the inside of a living body than transmissive and reflective types.

In order to solve the above problems, an information acquisition apparatus according to the present invention includes an output source that irradiates a target living body with detection waves, and a receiver capable of receiving the detection waves that have been applied to the target living body, wherein the output source and in the receiving section, an obtuse angle is formed between a direction in which the detection wave is emitted from the output source to the target living body and a direction from an irradiation location of the target living body irradiated with the detection wave to the receiving section. are arranged so that

According to the present invention, it is possible to provide an information acquisition apparatus that can more accurately and easily obtain information on the inside of a living body than transmissive and reflective types.

1 is a conceptual diagram of an information acquisition device according to a first embodiment; FIG. 1 is a schematic external view showing a measurement state of an information acquisition device according to a first embodiment; FIG. 4 is a photograph showing an example of an image acquired by the information acquisition device according to the first embodiment; It is a graph which shows the absorption rate of water and hemoglobin. 1 is a graph showing absorption spectra of hemoglobin (oxygenated hemoglobin, deoxygenated hemoglobin). It is a photograph showing an example of an image acquired by the information acquisition device according to the second embodiment. It is a photograph which shows an example of the image obtained with the information acquisition apparatus which concerns on 3rd Embodiment. It is a photograph which shows an example of the image obtained with the information acquisition apparatus which concerns on 4th Embodiment. 1 is a conceptual diagram of a conventional reflective information acquisition device; FIG. 1 is a conceptual diagram of a conventional transmissive information acquisition device; FIG.

An example of an embodiment of the technology of the present invention will be described below with reference to the drawings. In each drawing, the same or equivalent components and portions are given the same reference numerals. Also, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may differ from the actual ratios.

(First embodiment)
An information acquisition device 10 according to the first embodiment will be described with reference to FIGS. 1 to 6. FIG.
FIG. 1 is a conceptual diagram of the information acquisition device 10 according to the first embodiment, FIG. 2 is a schematic external view showing the measurement state of the information acquisition device 10 according to the first embodiment, and FIG. 4 is a graph showing absorption rates of water and hemoglobin, and FIG. 5 is hemoglobin (oxygenated hemoglobin, deoxygenated hemoglobin). FIG. 6 is a photograph showing an example of an image acquired by the information acquisition device 10 according to the first embodiment.

As shown in FIG. 1, an information acquisition apparatus 10 according to the present embodiment includes an output source 20 including an LED for irradiating a target living body (here, a human finger) with a detection wave, and a detection wave emitted to the target living body. and a receiving unit 30 capable of receiving waves.
Although not shown, the receiving section 30 includes a semiconductor device having pixels with photodetecting photodiodes, and a control section for controlling the detected light as a signal.
Although the output source 20 has an LED, a LASER DIODE or the like may be used.

The output source 20 and the receiving unit 30 have a direction in which the detection wave is emitted from the output source 20 to a finger of a human being, which is a target living body, and a direction from the irradiation point 100 of the target living body irradiated with the detection wave to the receiving unit 30. are arranged so that the angle between (angle A in FIG. 1) is an obtuse angle (an angle larger than 90 degrees and smaller than 180 degrees).
In the present embodiment, the light, which is the detection wave, is incident from the surface of the finger of the living body, which is the object to be imaged, in the direction in which the detection wave is emitted from the output source 20, and the incident detection wave hits the irradiated area. scatter. The receiving unit 30 captures an image of the scattered detection wave coming out of the finger of the living body. The irradiation site is, for example, the blood vessel (blood) of the finger. The detection wave strikes blood vessels and blood, is absorbed by hemoglobin in the blood, scatters, and exits the body.
The output source 20 and the receiving unit 30 are arranged such that the angle A formed by the half straight lines extending from the irradiation point 100 to the output source 20 and the receiving unit 30 from the irradiation point 100 to the output source 20 and the receiving unit 30 is obtuse. there is

Since the output source 20 and the receiving section 30 are arranged in an obtuse positional relationship, it is not necessary to pinch the finger of the living body, which is the object to be imaged, between the output source 20 and the receiving section 30 . Therefore, for example, as shown in FIG. 2, the information acquisition device 10 can measure a living body simply by placing a finger on the receiving section 30 .
In addition, compared with the conventional reflective type, the detection wave reflected by the surface of the living body is not received by the receiving section 30 as it is. The amount of light at which the light of the detection wave of the wavelength passes through and is attenuated is likely to be reflected as the absorbance.
In addition, the distance that the detection wave travels through the inside of the living body is shorter than that of the transmissive type, and the attenuation can be reduced accordingly.
Therefore, according to the present embodiment, it is easier to accurately obtain information on the inside of the living body than in the transmissive type and the reflective type.

In addition, in the present embodiment, measurement can be performed simply by placing a finger as shown in FIG. . Even in the transmissive type, it is not necessarily the case that the inserted finger is actually physically pinched and pressure, heat or the like is applied, causing pain or the like, and the injection needle is not pricked. However, for a test subject who has no experience or knowledge of what is done in the transmission type measurement, inserting the finger deeply into the measurement hole gives a psychological burden such as a sense of uneasiness and restraint.
In this embodiment, as shown in FIG. 2, the subject only needs to place his or her finger in a place where he/she can see it. Therefore, unlike the transparent type, the subject does not have to feel a psychological burden, and the subject can carry out the measurement with peace of mind. be able to.
According to this embodiment, it is possible to obtain the advantages of both the reflective type and the transmissive type.

FIG. 3 shows a photograph of a blood vessel 160 inside a living body (human finger) in this embodiment. In this photograph, while using a relatively low-power LED of 7 mW for the output source 20, the portion of the blood vessel 160 appears black (dark) due to light absorption by the hemoglobin 120, indicating that it can be sufficiently identified. ing.

Note that this embodiment is not limited to the configuration shown in FIG. Specifically, for example, a convex lens may be arranged between the irradiation point 100 of the living finger shown in FIG. 1 and the receiving section 30 . By arranging such a convex lens, it becomes possible to enlarge and image the blood vessel 160 .
Also, a non-contact thermometer that can measure the surface of a finger of a living body may be arranged. By measuring the temperature of the finger, it becomes possible to correct (calibrate) the absorbance.
Furthermore, for the purpose of calibration, a calibration optical sensor that measures the amount of light output from the output source 20 may be added separately.
In addition, the information acquisition device 10 according to the present embodiment can measure the oxygen saturation of arterial blood by simultaneously measuring the subject's pulse using a detection wave with a wavelength of around 800 nm. It also functions as a pulse oximeter.

(Second embodiment)
In the present embodiment, the wavelength of the detection wave output from the output source is limited to a specific wavelength in the first embodiment.
The above contents will be described in more detail below.
FIG. 4 shows the absorption rates of water 110 and hemoglobin 120, respectively.
The detection wave according to the present embodiment has a wavelength that can pass through a living body, and is light with a wavelength at which hemoglobin 120 has a higher absorbance than water 110 .
Here, the wavelength that can be transmitted through the living body includes a wavelength range that is easily transmitted through the living body, a wavelength range (650 nm to 950 nm) called the so-called “window 130 of the living body”.

The main light-absorbing substances present in the living body are water 110 and hemoglobin 120, which is an oxygen-transporting medium present in blood, and their absorption spectra strongly depend on the wavelength as shown in FIG. .
Visible light (300 nm to 700 nm) has a high absorption rate in hemoglobin 120, and the distance it can travel in the body is small.
Also, light with a wavelength longer than 1400 nm has a high absorption rate in water, and the distance it can travel in the body is very short.
Hemoglobin 120 and water 110 have weak absorption of near-infrared light in a wavelength range (650 nm to 950 nm) called the “living body window 130,” so near-infrared light in such a wavelength range does not penetrate inside the body. can penetrate deeply. For this reason, near-infrared light in such a wavelength range is often used in biomedical examinations using light, and this wavelength range is called the "living body window 130".

FIG. 5 shows absorption spectra of hemoglobin 120 (oxygenated hemoglobin 121 and deoxygenated hemoglobin 122).
Oxygenated hemoglobin 121 (indicated by a dotted line in FIG. 5), also called oxyhemoglobin, oxyhemoglobin HbO2, is hemoglobin 120 bound with oxygen and means the state of hemoglobin 120 in arterial blood.
Deoxygenated hemoglobin 122 (indicated by the solid line in FIG. 5), also called reduced hemoglobin or deoxyhemoglobin Hb, is hemoglobin 120 that is not bound to oxygen, and means the state of hemoglobin 120 in venous blood.

It should be noted that the "molecular extinction coefficient" on the vertical axis in FIG. 5 is a numerical value proportional to the absorbance when the measurement object is the same and the optical path length is the same.
Here, "absorbance" is a light attenuation coefficient (the degree to which light is weakened according to the optical path length in a substance) calculated based on Beer-Lambert's law, and is important information in vivo. It is used as a method for optically and noninvasively estimating the amount of blood components (oxygenated hemoglobin 121, deoxygenated hemoglobin 122, blood sugar level, etc.).

In the present embodiment, when an artery is to be detected, light having a wavelength at which oxygenated hemoglobin 121 has a higher absorbance than deoxygenated hemoglobin 122 is suitable for the detection wave.
Moreover, when veins are to be detected, the detection wave is suitable for light having a wavelength at which deoxygenated hemoglobin 122 has a higher absorbance than oxygenated hemoglobin 121 .

The above contents will be explained in other words with the graph of FIG.
The wavelength of the detection wave is shown in the graph (indicated by the dotted line in FIG. 5) showing the oxygenated hemoglobin 121 showing the relationship between the wavelength of the detection wave in arterial blood vessels and the molecular extinction coefficient of the detection wave, and the wavelength of the detection wave in venous blood vessels. The wavelength of the detection wave (805 nm), which is the intersection of the graph of deoxygenated hemoglobin 122 (shown by the solid line in FIG. 5) showing the relationship between the wavelength and the molecular extinction coefficient of the detection wave, and the biological window called the window of the biological body. is set between the maximum wavelength (950 nm) or the minimum wavelength (650 nm), which is the wavelength range of the detection wave that easily passes through the .

According to the present embodiment, for example, when biological information of an arterial blood vessel is measured, the wavelength of the detection wave is a graph (FIG. 5 ) and the graph (solid line in FIG. 5) showing the relationship between the wavelength of the detected wave and the molecular extinction coefficient of the detected wave in the vein blood vessel (solid line in FIG. 5). Furthermore, the wavelength of the detection wave is set to be less than the maximum wavelength (950 nm) of the "living body window", which is the wavelength range of the detection wave that easily passes through the living body. This makes it possible to make the absorbance of arterial blood vessels greater than that of venous blood vessels in this range.
As a result, the arterial blood vessels can be made darker (darker) than the venous blood vessels in the measurement image, making them more conspicuous, and the biometric information of the arterial blood vessels can be obtained more accurately.

Further, according to the present embodiment, for example, when biological information of a venous blood vessel is measured, the wavelength of the detection wave is a graph ( Dotted line in FIG. 5) and a graph (solid line in FIG. 5) showing the relationship between the wavelength of the detected wave and the molecular extinction coefficient of the detected wave in venous blood vessels. there is Furthermore, the wavelength of the detection wave is set to be equal to or greater than the minimum wavelength (650 nm) of the "living body window", which is the wavelength range of the detection wave that easily passes through the living body. This makes it possible to make the absorbance of venous vessels greater than that of arterial vessels in this range.
As a result, the venous blood vessels can be made darker (deeper) than the arterial blood vessels in the image obtained by the received detection waves, making them more conspicuous, and the biological information of the venous blood vessels can be obtained more accurately.

Therefore, when an artery is to be detected, light with a wavelength of 805 nm or more and less than 950 nm is suitable for the detection wave.
Moreover, when a vein is to be detected, light with a wavelength of 650 nm or more and less than 805 nm is suitable for the detection wave.

According to the present embodiment, by setting the wavelength of the detection wave to 805 nm or more and less than 950 nm, the molecular extinction coefficient of arterial blood vessels can be made larger than that of venous blood vessels within this range. (See Figure 5).
As a result, arterial blood vessels can be made darker (deeper) than venous blood vessels in an image obtained from the received detection waves, making them more conspicuous, and biometric information of the arterial blood vessels can be obtained more accurately.

According to this embodiment, by setting the wavelength of the detection wave to be less than 805 nm and 650 nm or more, the molecular extinction coefficient of venous blood vessels can be made larger than that of arterial blood vessels within this range. (See Figure 5).
As a result, the venous blood vessels can be made darker (darker) than the arterial blood vessels in the image obtained by the received detection waves, making them more conspicuous, and the biological information of the venous blood vessels can be obtained more accurately.

FIG. 6 is a photograph showing an example of an image acquired by the information acquisition device 10 according to this embodiment. FIG. 6A is an example of imaging at a wavelength of 850 nm, and FIG. 6B is an example of imaging at a wavelength of 940 nm.
In both cases, since the molecular extinction coefficient of the oxygenated hemoglobin 121 is higher than that of the deoxygenated hemoglobin 122, the arterial blood component can be more discriminated, and a detailed absorption image of the blood vessel 160 inside the living body can be obtained. can be done.

(Third Embodiment)
FIG. 7(A) is a photograph showing an example of an image obtained by the information acquisition device 10 according to the third embodiment, and FIG. 7(B) is a conceptual diagram showing portions of the image in FIG. be.
In the present embodiment, the receiving unit 30 receives the detected wave as an image, and extracts the contour line 150 of the target portion whose contour is a pixel whose pixel value difference is larger than that of the surrounding area by a threshold value or more in the received image. , calculate the absorbance only inside the contour 150 . Here, muscle and fat are formed around the blood vessel 160 .
Note that the outline 150 is created by a program installed in advance in the control means inside the receiving unit 30 so as to connect the outer edges of pixels whose pixel value difference is larger than the surrounding by a predetermined threshold or more. there is

According to the present embodiment, the outline 150 of the target portion of interest is extracted, the inside thereof is determined as the target portion, and the absorbance of only the inside thereof is calculated, thereby quantitatively calculating the absorbance. In addition, it is possible to obtain a more accurate value only for the target part (for example, only for the blood vessel 160), compared to the conventional case where the information for the part other than the blood vessel 160 with hemoglobin is also taken in and measured. Become.

(Fourth embodiment)
FIG. 8A is a photograph showing an example of an image obtained by the information acquisition device 10 according to the fourth embodiment, and FIG. 8B is a subdivided pixel group 170 extracted from FIG. It is a photograph which shows an example of the image obtained.
Receiving unit 30 according to the present embodiment divides the image in FIG. After subtracting the average value of the pixel values of the pixels from the pixel values of the entire pixels of the subdivided pixel group 170, the absorbance inside the outline 150 is calculated.
Here, muscle/fat 162 is included in the portion that does not include the target portion (for example, blood vessel 160).

According to the present embodiment, even if the output source 20 (e.g., illumination device) that outputs the detection wave does not uniformly hit the imaging part, the effect of uneven brightness of the background (background portion) is suppressed. It is possible to measure the absorbance with a more accurate quantitative value.

In the above-described first to fourth embodiments, light is used as the detection wave, but the detection wave is not necessarily limited to light. Since even sound is absorbed when propagating through a material, ultrasonic waves or the like in a predetermined vibration band may also be used.

10, 211, 312 Information acquisition device 20, 220, 320 Output source 30, 240, 350 Receiving unit 100 Irradiation point 110 Water 120 Hemoglobin 121 Oxygenated hemoglobin 122 Deoxygenated hemoglobin 150 Outline 160 Blood vessel 162 Muscle/fat 170 Subdivision pixel group

Claims (6)

an output source that irradiates a target living body with detection waves;
a receiving unit capable of receiving the detection wave irradiated to the target living body,
The output source and the receiving unit are
a direction in which the detection wave is emitted from the output source to the target living body;
An information acquisition device arranged so that an angle between a direction to the receiving unit and a location irradiated with the detection wave on the target living body is an obtuse angle. The detection wave is
2. The information acquisition device according to claim 1, wherein the light has a wavelength that can pass through the target living body and that has a higher absorbance for hemoglobin than for water. The detection wave is
When an artery is to be detected, oxygenated hemoglobin is light with a wavelength at which the absorbance is higher than that of deoxygenated hemoglobin,
3. The information acquisition device according to claim 2, wherein when veins are to be detected, deoxygenated hemoglobin has a wavelength at which absorbance is higher than that of oxygenated hemoglobin. when the artery is to be detected, the detection wave is light with a wavelength of 805 nm or more and less than 950 nm;
4. The information acquisition apparatus according to claim 3, wherein when the vein is to be detected, the detection wave is light with a wavelength of 650 nm or more and less than 805 nm. The receiving unit receives the detection wave as an image, extracts a contour line of a target portion whose contour is a pixel having a pixel value difference larger than a surrounding pixel value by a threshold value or more in the received image, and extracts the contour line. 5. The information acquisition device according to any one of claims 1 to 4, wherein the absorbance of only the inside is calculated. The receiving unit receives the detection wave as an image, divides the received image into a plurality of pixel groups, and averages pixel values of pixels in portions not including the target portion in each of the divided pixel groups. 6. The information acquisition apparatus according to claim 5, wherein the absorbance inside the contour line is calculated after subtracting the value from the pixel values of the entire pixels of the pixel group.

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